Tk::Photo images

An important part of the design of
Portable Presenter is the requirement for
screen-size independency; fonts and also images are scaled, dependent on
the actual screen-size.

You can defined Tk::Photo images in two ways:

Implicit: use an image in your slide description, for instance
with

$show->addSlide(-main => '<IMG SRC=image.xpm&gt');

In this case, you have created a Tk::Photo object, but are not able
to control it, although there are some options which you can use when
you use the markup formatter.

Explicit: define an image and refer to it later. For this, you have to
know that Tk::Photo objects are related to a MainWindow. A PPresenter show
can contain different viewports, so
you have to tell beforehand to which of them the image will be used.

The explicit way is demonstrated on this page. The implicit way is the
same for Tk::Photo objects and Image::Magick object, which is described
on the main image page.

The problem now, is that the image is defined for only one viewport: the
`selected viewport' of the show, in the first case (i.e. thè window
if you have only one); the viewport named `default' in the second case;
and the explicitly added viewport in the last case.

If you want to use an image for more than one viewport, you do not have
to take care yourself: PPresenter makes a copy for each viewport where it is
used in.

One PPresenter::Image object is created on the image() fuction
call, so you can specify the options for that object there. For objects
created this way, the default of -resize is off (0).

Example 1: Own symbols for unordered lists

Usually, the dots used to precede a list-item in an unordered list (for
instance used by the markup formatter),
is defined by the decoration option
-nestImages. The dots can be specified as filename or as
objects.